• Journal of the Korean Institute of Navigation
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• v.25 no.4
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• pp.407-415
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• 2001

In the present study, irregular disturbances to ship dynamics is proposed, where irregular disturbances implying irregular wave and the fluctuating component of wind for the evaluation of automatic steering system of ship in following seas. Prediction method based on the principle of linear superposition. Irregular wave disturbances in following seas is calculated by frequency variation method. The mathematical model of each element of an automatic steering system is derived, which takes account of a few non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. Performance index is introduced from the viewpoint of energy saving, which derived from the concept of energy loss on ship propulsion. Finally, the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of control constants of autopilot on propulsive energy loss are investigated

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.2
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• pp.173-180
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• 2013

In this paper, we studied on measurement of soil deformation around the tip of model pile by close-range photogrammetry. The rigorous bundle adjustment method was utilized to monitor the soil deformation in the laboratory model pile-load test as function of incremental penetration of the pile. Control points were installed on the frame of the laboratory model box case and more than 150 target points were inserted inside the soil around the model pile and on the surface. Four overlapping images including three horizontal and one vertical image were acquired by a non-metric camera for each penetration step. The images were processed to automatically locate the control and target points in the images for the self-calibration and the bundle adjustment. During the bundle adjustment, the refraction index of the acrylic case of the laboratory model was accounted for accurate measurement. The experiment showed the proposed approach enabled the automated photogrammetric monitoring of soil deformation around the tip of model pile.

• Current Optics and Photonics
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• v.7 no.2
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• pp.213-221
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• 2023

The optical window, as a part of the collimator system, is the connector between the outside light source and the optical system inside a vacuum tank. The temperature and pressure difference between the two sides of the optical window cause not only thermoelastic deformation, but also refractive-index irregularities. To suppress the influence of these two changes on the performance of the collimator system, thermo-optical analysis is employed. Coefficients that characterize the deformations and refractive-index distributions are derived through finite-element analysis, and then imported into the collimator system using a user-defined surface in ZEMAX. The temperature and pressure difference imposed on the window seriously degrade the system performance of the collimator. A decentered and tilted lens group is designed to correct both field aberrations and the thermal effects of the window. Through lens-interval adjustment of the lens group, the diffraction-limited performance of the collimator can be maintained with a vacuum level of 10^-5 Pa and inside temperature ranging from -100 ℃ to 20 ℃.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.101-110
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• 2003

This paper introduces an identification method for nonlinear models in the form of rule-based Fuzzy-Neural Networks (FNN). In this study, the development of the rule-based fuzzy neural networks focuses on the technologies of Computational Intelligence (CI), namely fuzzy sets, neural networks, and genetic algorithms. The FNN modeling and identification environment realizes parameter identification through synergistic usage of clustering techniques, genetic optimization and a complex search method. We use a HCM (Hard C-Means) clustering algorithm to determine initial apexes of the membership functions of the information granules used in this fuzzy model. The parameters such as apexes of membership functions, learning rates, and momentum coefficients are then adjusted using the identification algorithm of a GA hybrid scheme. The proposed GA hybrid scheme effectively combines the GA with the improved com-plex method to guarantee both global optimization and local convergence. An aggregate objective function (performance index) with a weighting factor is introduced to achieve a sound balance between approximation and generalization of the model. According to the selection and adjustment of the weighting factor of this objective function, we reveal how to design a model having sound approximation and generalization abilities. The proposed model is experimented with using several time series data (gas furnace, sewage treatment process, and NOx emission process data from gas turbine power plants).

• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.65-70
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• 2005

Evaluation of repetitiveness for upper extremity intensive tasks is essential to determine the level of risk for upper extremity musculoskeletal disorders at the workplace. However, experimental data available to establish the acceptable levels of repetitiveness for various postures and forces is lacking. The present study examined the maximum acceptable frequencies(MAFs; motions/min.) of shoulder, elbow, wrist, and index finger motions at different forces(1kgf and 4kgf for shoulder, elbow, and wrist; 0.25kgf and 1 kgf for index finger) in sitting. Seventeen right-handed males in 20s without having any history musculoskeletal disorders participated in the MAF experiment. The participants determined their MAFs for the upper extremity motions by using the self-adjustment method and their work pulse(increase in heart rate; beats/min.) and rating of perceived exertion(RPE) were measured when working at MAF. The MAFs of elbow, wrist, and index finger motions for each force level were about 2, 3, and 6 times the corresponding MAF(9 at the high force and 24 at the low force) of shoulder motion and the MAFs at the low force increased about 2 times those at the high force. The work pulses of elbow, wrist, and index finger motions for each force level were 70%, 50%, and 30% of the corresponding work pulse(17 at the high force and 12 at the low force) of shoulder motion and the work pulses at the low force were about 70 % of those at the high force. Lastly, the RPEs of the upper extremity regions were about level 3(moderate) or below.

• The Journal of Korean Medicine
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• v.37 no.3
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• pp.112-122
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• 2016

Objectives: This study aimed to assess the validity of 'Korean Diagnosis Related Groups-Korean Medicine (KDRG-KM)' which was developed by Health Insurance Review & Assessment Service (HIRA) in 2013 Methods: Among inpatient EDI claim data issued by hospitals and clinics in 2012, the data which included Korean medicine procedures were selected and analyzed. We selected control targets in the Korean medicine hospitals which had longer Episodes-Costliness index (ECI) and Lengthiness index (LI) than average of total Korean medicine hospitals, and compared the results of selection between the major diagnosis-based patient classification system and the KDRG-KM system. Finally, the explanation power (R2) and coefficient of variation (CV) of the KDRG-KM system using practice expenses were calculated. Results: The numbers of control target in Korean medicine hospitals changed from 36 to 32 when patient grouping adjustment method was changed from major diagnosis to KDRG-KM. For expenses of all outpatient claim data on Korean medicine, explanation power of KDRG-KM system was 66.48% after excluding outliers. CVs of expenses of patient groups in Korean medicine hospitals were gathered from under 70% to under 90%, and those in long-term care hospitals mostly belonged under 70%. Conclusions: The validity of KDRG-KM system was assured in terms of explanation power. By adapting KDRG-KM system, fairness of control targets selection for costliness management in Korean medicine hospitals can be enhanced.

• Therapeutic Science for Rehabilitation
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• v.11 no.4
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• pp.41-53
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• 2022

Objective : The purpose of this study is to identify and analyze the vocational rehabilitation evaluation tool for the mentally disabled. Methods : For literature search, the Pubmed database was used, and for the analysis, the development year, evaluation method, number of items, scale, and evaluation items were analyzed. In the analysis method, each evaluation item was divided into four categories: function, internal factor, environment, and mental symptom, and the evaluation elements of each evaluation tool were identified. Results : When searching Pubmed through search terms, 161 documents were retrieved. According to the selection method, Griffiths Work Behavior Scale (GWBS), Occupational Functioning Scale (OFS), Social and Occupational Functioning Assessment Scale (SOFAS), Work Ability Index (WAI), Work Behavior Inventory (WBI), Work Environment Impact Scale (WEIS), and Work and Social Adjustment Scale (WSAS) were screened. The evaluation items of all evaluation tools included job-related functional evaluation. According to the purpose of each evaluation tool, internal factors, environment, and mental symptoms were measured. Conclusion : Occupational skills are skills in which various functions such as physical, cognitive, social skills, and coping skills act in a complex way. Therefore, it is necessary to include the four factors analyzed in this study: function, internal factors, environment, and psychiatric symptoms.

• 대한예방의학회:학술대회논문집
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• 1998.10b
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• pp.258-259
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• 1998

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.183-194
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• 2021

In this study, the conversion factor for 2020 is estimated based on an outpatient and inpatient conversion factor separation model developed from SGR and AR by using actual medical expense data. In addition, a policy plan is proposed to calculate the values of single and multiple conversion factors for each type of medical expense, and to effectively use the conversion factor separation model as one of the means to establish a medical delivery system. The major results are as follows. First, at r=0.1, the rate of adjustment in the hospital single conversion index in 2020 was 2.0%, and the outpatient and hospitalization conversion rates for hospitals were 2.2% and 2.3%, respectively. In addition, a combination of outpatient and inpatient conversion factors can be used for the adjustment. Second, as a measure to establish a medical delivery system, instead of adjusting the addition rate, a method of interlocking the addition rate and the conversion factor is proposed. Third, it is necessary to develop a model that enables target management of volumes, in addition to the outpatient conversion factor, the inpatient conversion factor, and the adjustment coefficient.

• Korean Journal of Occupational Health Nursing
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• v.17 no.1
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• pp.86-95
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• 2008

Purpose: The objectives for this study are to produce the comprehensive management indexes and find their application strategies for appropriate medical care in primary care clinics under workers' compensation insurance. Method: Data of this study was workers' compensation insurance medical fees claim's data from July 2006 to June 2007. Data were analyzed using SAS 9.1 version by applying descriptive statistics and Pearson's correlation. The indexes such as costliness index(CI), standard medical fee were calculated based on the fourth revision of korean classification of diseases(KCD-4.). Results: The CI, visiting index(VI), outliers index(OI), and medical review adjustment percentage were positively correlated in the both inpatient and outpatient medical fees in primary care clinics under workers' compensation insurance. The major medical specialities were neurological surgery, general medicine, general surgery, rehabitational medicine, and orthopedic surgery. The CIs were slightly high in rehabitational medicine among major medical specialities. The CIs were mostly high in diagnosis, test, anesthesia, and rehabitational assistive device fees among major medical specialities. The CIs were slightly high in Kwangju, Daegu, Daejeon, and Busan districts among district management centers of Korea Workers' Compensation and Welfare Service. Conclusions: We suggest the continuous development of appropriate disease classification system and medical care quality indicators to successfully take root the comprehensive management for appropriate medical care under workers' compensation.